The lateral bone of the forearm that is located between the elbow and the hand and that is always aligned with the thumb is called the radius bone. "Lateral" is a term that refers to the side of the body or the position that is farthest away from the mid-line of the torso when the body is in what is known as the anatomical position, described as a person who is standing facing forward with the palms of his or her hands also turned forward. Palpating the lower arm might feel like there is only one, somewhat flat bone in the extremity, but the forearm is supported and shaped by two distinct bones: the radius bone and the ulna bone.
Part of the radial artery, which is a blood vessel and one of the major suppliers of oxygenated blood to the lower arm, lies close to the surface of the body and crosses over the radius bone, creating the radial pulse, which derives its name from the radius and can be palpated with a fingertip. This is the area that most often is felt by healthcare providers to take a person's pulse, a vital sign of life. It is, however, a peripheral pulse and usually is not checked to verify whether a person is alive.
There are different categories into which all of the approximate 206 bones comprising the skeleton belong: long, short, irregular and flat. The radius bone is considered long. Growth of the body occurs in long bones, in what are known as growth plates, by an increase in the length of the bones of the arms, legs and back.
Fractures of the radius bone can cause swelling, deformity and severe discomfort, but the signs of swelling and deformity might not be very visible if the ulna is uninjured. The same can be true in cases involving a fracture of the ulna but no injury to the radius. X-rays of the extremity are taken to reveal any fractures that need to be treated.
Medical intervention by emergency medical technicians for patients with any deformity and tenderness in the forearm usually involves applying tension while splinting the extremity using a padded and rigid splint. Application of a sling and swathe generally follows splinting. The shaft of the radius bone, like all long bones, is slightly curved, although it appears to be straight when viewing X-rays, drawings or photographs of this part of the skeleton.